minor #14873 [Validator] Use double quotes instead of single (wkania)

This PR was merged into the 4.4 branch.

Discussion
----------

[Validator] Use double quotes instead of single

<!--

If your pull request fixes a BUG, use the oldest maintained branch that contains
the bug (see https://symfony.com/releases for the list of maintained branches).

If your pull request documents a NEW FEATURE, use the same Symfony branch where
the feature was introduced (and `5.x` for features of unreleased versions).

-->

Commits
-------

29a2545 [Validator] Use double quotes instead of single

Author: javiereguiluz

reference/constraints/IsFalse.rst

@@ -97,7 +97,7 @@ method returns **false**:
             public static function loadValidatorMetadata(ClassMetadata $metadata)
             {
                 $metadata->addGetterConstraint('stateInvalid', new Assert\IsFalse([
-                    'message' => 'You've entered an invalid state.',
+                    'message' => "You've entered an invalid state.",
                 ]));
             }
         }